1. Field of the Invention
The invention relates to a memory device and fabrication thereof, and more particularly relates to a phase change memory device and fabrication thereof.
2. Description of the Related Art
Phase change memory devices have many advantages, such as high speed, lower power consumption, large capacity, greater endurance, better process integrity and lower cost. Phase change memory devices can thus be used as independent or embedded memory devices with high data integrity. Due to the described advantages and others, phase change memory device may replace flash memory.
To serve as a viable alternative, phase change memory technology requires highly reliable, high-speed, low-current, low-voltage operation. Current phase change memory technology employs heating at the interface between a metal electrode contact and the phase change material. This heating method is highly inefficient, however, and requires a lengthy programming duration of up to several hundred nanoseconds, and may also require a substantial amount of current (0.5 mA or greater). The described inefficient heating is also characterized by non-uniform temperature distribution within the phase change region, diminishing reliability due to accumulation of incomplete phase change in the programming volume. It is thus desirable to devise a phase change memory cell structure design that avoids these disadvantages.